The plot is thickening in the seemingly never-ending Raj Rajaratnam saga.

On Friday, a lawyer representing former McKinsey & Co. Partner and Goldman Sachs Group Inc. Director Rajat Gupta said an unidentified person at Goldman was caught on a wiretap leaking confidential information to Raj Rajaratnam, the Galleon Group founder who currently is serving an 11-year prison term for insider trading.

Last year, the Securities and Exchange Commission brought civil charges against Gupta, accusing him of leaking secrets to Rajaratnam. Federal prosecutors expanded their charges against Gupta last month, claiming his scheme with Rajaratnam began earlier than they originally thought. Gupta faces five counts of securities fraud and one count of conspiracy. He also faces separate criminal charges for allegedly tipping Rajaratnam with Goldman and Procter & Gamble Co. secrets. Gupta’s trial is scheduled to begin in May.

At Friday’s pre-trial hearing, Gupta’s lawyer told U.S. District Judge Jed Rakoff that a U.S. prosecutor disclosed in a letter that the government has wiretap evidence of another source at Goldman who told Rajaratnam secrets concerning Apple Inc. and Intel Corp. He also told the judge that he believes “there is a much more circumstantial case that [the unidentified Goldman source] should be sitting in the box rather than us” and that “the wrong man is on trial here.”